Froth in the front of top aligners, aligner doesn't feel like it's exerting pressure on the second day.

I think my top aligners may be loose. When I press the front of them while they're seated on my teeth, the entire tray tilts backwards and separates off of my palate. There's also a froth on the front, which I thought isn't supposed to happen (aren't they supposed to be airtight?) They're also far easier to take off than the lower ones, and I can push them off my teeth with my upper lip.

No doctor answers yet